Apparatus for transporting stacks of sheets or the like

ABSTRACT

Transporting apparatus for stacks of sheets in bookbinding or like machines has an endless chain coupled to equidistant holders which can transport stacks past one or more processing stations. Each holder has a first jaw which is coupled to the chain and is confined to movement in a stationary guide member to prevent tilting or other stray movements of the holder with reference to the chain, and a second jaw which is movable toward and away from the first jaw and carries a set of parallel toothed racks meshing with pinions which are mounted on a shaft rotatable in a bore of the first jaw. A torsion spring biases the second jaw toward the first jaw, and a helical spring serves to normally hold the second jaw against movement toward the first jaw but to permit movement of the second jaw away from the first jaw under the action of cams which can be engaged by a follower provided on the second jaw. The means for disengaging the helical spring from the shaft for the pinions in order to permit movements of the second jaw toward the first jaw under the action of the torsion spring comprises a rod which engages one end of the helical spring and has a follower which can engage one or more stationary cams adjacent to the path of the holders to thereby enlarge the internal diameters of convolutions of the helical spring and to thus cause its disengagement from the shaft.

[ 51 June 13, 1972 [54] APPARATUS FOR TRANSPORTING STACKS OF SHEETS OR THE LIKE Walter Risi, Frauenfeld, Switzerland Martini Buchbindereimaschinenfabrik AG, Frauenfeld, Switzerland [22] Filed: March 12,1971

[21] Appl.No.: 123,531

[72] Inventor:

[73] Assignee:

Primary Examiner-Richard E. Aegerter Attarney-Michael S. Striker [57] ABSTRACT Transporting apparatus for stacks of sheets in bookbinding or. like machines has an endless chain coupled to equidistant holders which can transport stacks past one or more processing stations. Each holder has a first jaw which is coupled to the chain and is confined to movement in a stationary guide member to prevent tilting or other stray movements of the holder with reference to the chain, and a second jaw which is movable toward and away from the first jaw and carries a set of parallel toothed racks meshing with pinions which are mounted on a shaft rotatable in a bore of the first jaw. A torsion spring biases the second jaw toward the first jaw, and a helical spring serves to normally hold the second jaw against movement toward the first jaw but to permit movement of the second jaw away from the first jaw under the action of cams which can be engaged by a follower provided on the second jaw. The means for disengaging the helical spring from the shaft for the pinions in order to permit movements of the second jaw toward the first jaw under the action of the torsion spring comprises a rod which engages one end of the helical spring and has a follower which can engage one or more stationary cams adjacent to the path of the holders to thereby enlarge the internal diameters of convolutions of the helical spring and to thus cause its disengagement from the shaft.

1 1 Claims, 4 Drawing Figures FIGJ ' INVENTOR.

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' PATENIEBJux 13 m2 3.669246 sum 3 0F 4 INVENTOR. 044m 2 14'1" APPARATUS FOR TRANSPORTING STACKS OF SHEETS OR THE LIKE BACKGROUND OF THE INVENTION The present invention relates to apparatus for transporting stacks of sheets or the like, particularly in bookbinding machines. Still more particularly, the invention relates to improvements .in apparatus for transporting stacks of sheets or the like past one or more processing or treating stations.

Presently known apparatus for the transport of stacks of sheets, portions of books, finished books or like commodities normally comprise a conveyor and a set of clamps which serve to transport the commodities along an endless path and past one or more processing stations. As a rule, the conveyor carries relatively long clamps which are capable of transporting customary simple stacks as well as twin or double stacks. A drawback of relatively long clamps is that their jaws are likely to tilt in response to engagement with and retention of stacks consisting of relatively small sheets. Tilting of the jaws with reference to each other causes a movement of their clamping surfaces out of positions of parallelism with each other; such misalignment of clamping surfaces results in non-uniform retaining action and affects the quality of the final product.

It is also known to mount on the conveyor a set of interconnected clamps which can carry partly finished or finished books along a predetermined path and past a desired number of treating stations. Each clamp has two jaws which are mirror symmetrical with reference to each other and are movable relative to each other by rack and pinion drives. The clamps are mounted on supports which are linked to each other to constitute the conveyor. The supports must be properly guided to insure satisfactory orientation of the jaws during engagement with, during retention and during disengagement from the stacks. Satisfactory guidance of such supports necessitates the use of complicated and costly equipment. Furthermore, the sprockets for the conveyor consisting of supports for the claws must be mounted on shafts which should have certain freedom of lateral movement in order to insure that the supports can travel around the end turns from one strength to the other, i.e., to compensate for the so-called polygon effect. Such mounting of the shafts, too, contributes to the complicatedness of the transporting apparatus.

SUMMARY OF THE INVENTION An object of the invention is to provide a novel and improved apparatus for transporting stacks of sheets (such as portions of or complete books) through one or more treating or processing stations in bookbinding or like machines.

Another object of the invention is to provide the transporting apparatus with novel and improved holders which can properly engage and retain stacks of smaller or larger sheets as well as relatively thick or relatively thin stacks, and which can be guided with a higher degree of accuracy and with smaller outlay for equipment than in presently known transporting apparatus.

A further object of the invention is to provide a transporting apparatus wherein the holders need not be provided with discrete supports for the jaws and wherein the holders can readily travel along straight as well as along arcuate portions of their path.

An additional object of the invention is to provide novel means for guiding travelling holders for stacks of sheets in bookbinding or like machines and to provide novel means for closing and opening the jaws of such holders in selected portions of their path.

Still another object of the invention is to provide a transporting apparatus which can be readily installed in many presently known bookbinding or like machines and wherein the jaws of the holders cannot become misaligned irrespective of the size and number of sheets in the commodities which must be transported by such holders.

The improved transporting apparatus comprises a conveyor, preferably an endless link chain located in a substantially horizontal plane, which defines an endless path, at least one holder or clamp including a first gripper or jaw mounted directly on the conveyor for. movement along the endless path and a second gripper or jaw which is movable toward and away from the first gripper to permit retention or removal of a stack of sheets (e.g., a partly finished or completed book) which is located between the grippers, cam means adjacent to the path, follower means provided on the second gripper to move the latter away from the first gripper in response to engagement with the cam means, and stationary guide means engaging directly with the first gripper to maintain the latter in a predetermined position with reference to the conveyor, at least while the holder travels along at least one predetermined portion of the endless path, for example, along one or more straight stretches of the endless chain.

In accordance with another feature of the invention, the holder further comprises biasing means (e.g., a torsion spring) for urging the second gripper toward the first gripper, pinion means rotatably mounted in one of the grippers, and toothed rack means parallel to the direction of movement of the second gripper with reference to the first gripper and meshing with the pinion means. The rack means is rigid with the other gripper and is reciprocable in ways provided therefor in the one gripper.

The novel features which are considered as characteristic of the invention are set forth in particular in the appended claims. The improved transporting apparatus itself, however, both as to its construction and its mode of operation, together with additional features and advantages thereof, will be best understood upon perusal of the following detailed description of certain specific embodiments with reference to the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a fragmentary plan view of a portion of a transporting apparatus which embodies the invention;

FIG. 2 is a front elevational view of the structure shown in FIG. 1 as seen in the direction of the arrow ll;

FIG. 3 is a transverse vertical section as seen in the direction of arrows from the line III-III of FIG. 1 or 2; and

FIG. 4 is a transverse vertical sectional view as seen in the direction of arrows from the line IV-IV of FIG. 1 or 2.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The improved transporting apparatus comprises a conveyor including an endless chain 1 which is disposed in a substantially horizontal plane and is trained over at least two sprockets, not shown. The chain 1 supports a set of equidistant holders or clamps 2 (only one shown) each of which comprises two relatively movable grippers or jaws 3 and 4. The aforementioned polygon effect is avoided by spacing the hol ders from each other. This also allows for the use of small sprockets for the chain 1.

The jaw 3 of the illustrated clamp 2 is articulately connected to the chain 1 and is guided by a stationary guide member 7 of the transporting apparatus in accordance with a feature of the present invention. The illustrated jaw 4 is movable toward and away from and is guided by the jaw 3. As shown in FIGS. 3 and 4, the jaws 3, 4 have gripping or clamping surfaces 5, 6 which are parallel to each other and which can engage the outermost sheets of a stack ST.

The stationary guide member 7 has two horizontal guide surfaces 8 and 9 (see FIGS. 3 and 4) which are parallel to each other and serve to confine the holder 2 against movement in a substantially vertical plane at right angles to the plane of the chain 1. The jaw 3 has four horizontal shafts 10, ll, l2, 13

which respectively carry idler rollers or wheels 14,15, 16, 17.

in a plane which is parallel to the plane of the chain 1. The jaw 3 is provided with four bearing members 22, 23, 24, 25; the bearing members 22 and 24 have upwardly extending stub shafts 26, 27 and the bearing members 23, 25 have downwardly extending stub shafts 28, 29. The stub shafts 26, 28, 27, 29 respectively carry pairs of coaxial idler rollers or wheels 30, 31, 32 and 33. The rollers 30, 32 and 31, 33 respectively track the guide surfaces 1819 and 21-22 so that the holder 2 is positively guided against upward, downward or lateral movement and is compelled to follow a predetermined path along each elongated stringer or stretch of the chain 1. The stub shaft 27 at the front end of the jaw 3 is coaxial with a pintle 101 of the chain 1 which is articulately connected with the jaw 3 so the latter pivot about the common axis of the stub shaft 27 and the respective pintle 101. The jaw 3 is further coupled to the chain 1 by way of the bearing members 22 and 23 which are located at the trailing end of the holder 2. Those surfaces of the bearing members 22, 23 which face the chain 1 are provided with U-shaped recesses or grooves 35, 36 which receive the adjacent pintle 101 of the chain 1 to thus insure that the holder 2 is free to travel around the end turns of the chain, i.e., around the respective sprockets for the chain links 102.

The jaw 4 of the holder 2 is provided with two parallel guide rods 37, 38 which are normal to the clamping surface 6 and are reciprocable in ways 40, 41 provided therefor in the jaw 3. Each of the guide rods 37, 38 constitutes a toothed rack which meshes with one of two pinions 45, 46 mounted on a shaft 44 by way of needle bearings 42, 43. The shaft 44 is rotatable in a bore 41 of the jaw 3. The pinions 45, 46 are held against axial and/or angular movement with reference to the shaft 44. The parts 37, 38 and 44-46 insure that the jaw 4 can move with reference to the jaw 3 (toward and away from the clamping surface but that it cannot change its orientation, i.e., that the clamping surface 6 remains at all times parallel to the clamping surface 5. The axis of the shaft 44 is parallel to the planes of the clamping surfaces 5, 6.

Those ends of the guide rods 37, 38 which are remote from the jaw 4 are rigidly connected to each other by means of a crosshead or yoke 47 which constitutes a follower and can engage suitably distributed roller-shaped cams 50, mounted on shafts 49 (only one shown), to move the jaw 4 away from the jaw 3. The crosshead 47 is reinforced by a web 48. FIG. 1 shows that, when the chain 1 advances in the direction indicated by the arrow A and the follower 47 reaches a cam 50, the jaw 4 moves away from the jaw 3 whereby the racks 37, 38 move with reference to and rotate the respective pinions 45, 46 and the shaft 44 to insure that the orientation of the jaw 4 with reference to the jaw 3 remains unchanged. The biasing means for urging the jaw 4 toward the jaw 3 comprises a torsion spring 51 whose convolutions surround the shaft 44 for the pinions 45 46 and one end portion 52 of which is secured to the jaw 3. The other end portion 53 of the torsion spring 51 is secured to the shaft 44. When the holder 2 is opened, i.e., when the jaw 4 is moved away from the jaw 3 to permit insertion or withdrawal of a stack ST from the space between the clamping surfaces 5, 6, the torsion spring 51 stores energy and tends to return the clamping surface 6 toward the clamping surface 5 to thereby safely clamp the outermost sheets of a freshly inserted stack ST. The bias of the torsion spring 51 is preferably adjustable in any well known manner to thus permit for accurate selection of the force with which a stack ST is held between the clamping surfaces 5 and 6.

The transporting apparatus is further provided with blocking or retaining means for maintaining the holder 2 in the open position, i.e., for preventing (when necessary) immediate return movement of the jaw 4 toward the jaw 3 (under the action of the torsion spring 51) when the follower 47 moves beyond a cam 50. The blocking means com rises a helical spring 54 which is mounted on the shaft 44 and one end portion 55 of which is fixed to the jaw 3. When the blocking or retaining spring 54 is in unstressed condition, the internal diameter of its convolutions substantially equals the diameter of the shaft 44. When the shaft 44 rotates in the direction to pemiit movement of the jaw 4 away from the jaw 3, i.e., when the spring 51 is caused to store energy, the internal diameter of the convolutions of the blocking or retaining spring 54 increases. On the other hand, the internal diameter of the convolutions of the spring 54 decreases when the shaft 44 tends to rotate under the action of the torsion spring 51, i.e., while the jaw 4 tends to move toward the jaw 3. The convolutions of the spring 54 then engage the external surface of the shaft 44 with such force that the torsion spring 51 is unable to move the jaw 4 toward the jaw 3. The second end portion 56 of the blocking or retaining spring 54 bears against the end face of a reciprocable disengaging member or bar 57 which is movable axially in the jaw 3 and the other end of which carries a roller follower 58. The shaft 59 of the roller follower 58 is rotatable in a lever 60 which is pivotable on a pin 62 of the jaw 3. The lever 60 is biased in a clockwise direction, as viewed in FIG. 2, either by the end portion 56 of the spring 54 and/or by a separate spring, so that the roller follower 58 bears against a stationary carrier 63 which is provided with one or more suitably positioned projections or cams 63a causing the bar 57 to move axially and to shift the end portion 56 of the blocking or retaining spring 54 so that the latters internal diameter increases whereby the shaft 44 is free to rotate under the action of the torsion spring 51 in order to move the jaw 4 toward the jaw 3 and to clamp the stack ST to the holder 2. The mounting of the springs 51 and 54 in the jaw 3 contributes to compactness of the holder 2.

The operation:

The chain 1 is driven by one of its sprockets so as to advance the holders 2 along an endless path. The holders 2 are preferably equidistant from each other. If the jaw 4 of a selected holder 2 bears against the respective jaw 3 under the action of the torsion spring 51 while the holder approaches a cam 50, the latter shifts the jaw 4 away from the jaw 3 through the intermediary of the follower 47 so that the holder 2 opens. Such opening takes place in a predetermined portion of the endless path for the holders 2. The torsion spring 51 then tends to return the jaw 4 into engagement with or nearer to the jaw 3 but the blocking or retaining spring 54 holds its convolutions in strong frictional engagement with the peripheral surface of the shaft 44 so that the movement of the jaw 4 toward the jaw 3 can take place only when the roller follower 58 of the respective disengaging bar 57 reaches the nearest cam 63a of the stationary carrier 63. The end face of the bar 58 then displaces the end portion 56 of the spring 54 in a direction to increase the internal diameter of the convolutions of the spring 54 so that the torsion spring 51 can take over in order to move the jaw 4 toward the jaw 3 until the clamping surfaces 5, 6 engage the adjacent outermost sheets of a stack ST which is inserted into the space between the clamping surfaces 5, 6 in the open position of the respective holder 2. The length of each cam 63a is sufficient to insure that the shaft 44 can rotate long enough to guarantee that the clamping surfaces 5 6 properly engage and hold the stack ST. The mechanism which inserts the stacks ST into the holders 2 is not shown in the drawing; the construction and mode of operation of such mechanism form no part of the present invention.

Each stack ST is transported by the respective holder 2 past one or more processing or treating stations and can be removed from the respective holder when the follower 47 reaches the nearest cam 50.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features which fairly constitute essential characteristics of the generic and specific aspects of my contribution to the art and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the claims.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims 1. Apparatus for transporting stacks of sheets past one or more treating stations, particularly in a bookbinding machine, comprising a conveyor defining an endless path; a holder including a first gripper mounted on said conveyor for travel along said path, a second gripper movable toward and away from said first gripper to permit retention and removal of a stack of sheets which is located between said grippers, biasing means for urging said second gripper toward said first gripper, pinion means rotatably mounted in one of said grippers, toothed rack means parallel with the direction of movement of said second gripper relative to said first gripper and meshing with said pinion means, said rack means being secured to the other gripper and said one gripper having ways for said rack means; cam means adjacent to said path; follower means provided on said second gripper to move said second gripper away from said first gripper in response to engagement with said cam means; and stationary guide means engaging with said first gripper to maintain the first gripper in a predetermined position with reference to said conveyor at least while said holder travels along at least one predetermined portion of said path.

2. Apparatus as defined in claim 1, wherein said conveyor comprises an endless flexible element and further comprising additional holders mounted on longitudinally spaced portions of said flexible element.

3. Apparatus as defined in claim 1, wherein said rack means comprises a plurality of parallel racks secured to said second gripper and said pinion means comprises a plurality of coaxial pinions rotatably mounted in said first gripper and each meshing with a different rack.

4. Apparatus as defined in claim 3, wherein said grippers have parallel stack-engaging clamping surfaces and the common axis of said pinions is parallel to said clamping surfaces.

5. Apparatus as defined in claim 4, further comprising a shaft rotatably mounted in said first gripper and rigid with said pinions, said biasing means comprising a torsion spring surrounding said shaft and having first and second end portions respectively secured to said shaft and to said first gripper, said torsion spring being arranged to bias said pinions to rotate in a direction to move said second gripper toward said first gripper and to store energy in response to movement of said second gripper away from said first gripper.

6. Apparatus as defined in claim 1, further comprising a shaft rotatably mounted in said first gripper and rigid with said pinion means, and blocking means for temporarily retaining said second gripper against movement toward said first gripper under the action of said biasing means.

7. Apparatus as defined in claim 6, wherein said blocking means comprises a helical spring having convolutions surrounding said shaft, a first end portion secured to said first gripper and a second end portion, the convolutions of said helical spring being arranged to normally grip said shaft and to hold the latter against rotation in a direction to pennit movement of said second gripper toward said first gripper, and further comprising disengaging means operative to disengage said convolutions from said shaft in response to movement of said holder along at least one predetermined portion of said path.

8. Apparatus as defined in claim 7, wherein said disengaging means comprises a reciprocable member engaging the second end portion of said helical spring at one end and having second follower means at the other end thereof, and second cam means adjacent to said predetermined portion of said path, said reciprocable member being arranged to move said second end portion of said helical spring in a direction to in crease the diameters of said convolutions in response to engagement between said second follower means and said second cam means to thereby enable said biasing means to move said second gripper toward said first gripper.

9. Apparatus as defined in claim 1, wherein said conveyor comprises an endless chain and a plurality of additional holders mounted on said chain, said holders being equidistant from each other.

10. Apparatus as defined in claim 1, wherein said conveyor comprises an endless chain having a plurality of links and pintles articulately connecting said links to each other, said first gripper being pivotably connected with at least one of said pintles.

11. Apparatus as defined in claim 10, wherein said first gripper has a front portion and a rear portion, as considered in the direction of movement of said holder along said path, said front portion being pivotably connected with said one pintle and said rear portion having at least one elongated groove receiving another one of said pintles. 

1. Apparatus for transporting stacks of sheets past one or more treating stations, particularly in a bookbinding machine, comprising a conveyor defining an endless path; a holder including a first gripper mounted on said conveyor for travel along said path, a second gripper movable toward and away from said first gripper to permit retention and removal of a stack of sheets which is located between said grippers, biasing means for urging said second gripper toward said first gripper, pinion means rotatably mounted in one of said grippers, toothed rack means parallel with the direction of movement of said second gripper relative to said first gripper and meshing with said pinion means, said rack means being secured to the other gripper and said one gripper having ways for said rack means; cam means adjacent to said path; follower means provided on said second gripper to move said second gripper away from said first gripper in response to engagement with said cam means; and stationary guide means engaging with said first gripper to maintain the first gripper in a predetermined position with reference to said conveyor at least while said holder travels along at least one predetermined portion of said path.
 2. Apparatus as defined in claim 1, wherein said conveyor comprises an endless flexible element and further comprising additional holderS mounted on longitudinally spaced portions of said flexible element.
 3. Apparatus as defined in claim 1, wherein said rack means comprises a plurality of parallel racks secured to said second gripper and said pinion means comprises a plurality of coaxial pinions rotatably mounted in said first gripper and each meshing with a different rack.
 4. Apparatus as defined in claim 3, wherein said grippers have parallel stack-engaging clamping surfaces and the common axis of said pinions is parallel to said clamping surfaces.
 5. Apparatus as defined in claim 4, further comprising a shaft rotatably mounted in said first gripper and rigid with said pinions, said biasing means comprising a torsion spring surrounding said shaft and having first and second end portions respectively secured to said shaft and to said first gripper, said torsion spring being arranged to bias said pinions to rotate in a direction to move said second gripper toward said first gripper and to store energy in response to movement of said second gripper away from said first gripper.
 6. Apparatus as defined in claim 1, further comprising a shaft rotatably mounted in said first gripper and rigid with said pinion means, and blocking means for temporarily retaining said second gripper against movement toward said first gripper under the action of said biasing means.
 7. Apparatus as defined in claim 6, wherein said blocking means comprises a helical spring having convolutions surrounding said shaft, a first end portion secured to said first gripper and a second end portion, the convolutions of said helical spring being arranged to normally grip said shaft and to hold the latter against rotation in a direction to permit movement of said second gripper toward said first gripper, and further comprising disengaging means operative to disengage said convolutions from said shaft in response to movement of said holder along at least one predetermined portion of said path.
 8. Apparatus as defined in claim 7, wherein said disengaging means comprises a reciprocable member engaging the second end portion of said helical spring at one end and having second follower means at the other end thereof, and second cam means adjacent to said predetermined portion of said path, said reciprocable member being arranged to move said second end portion of said helical spring in a direction to increase the diameters of said convolutions in response to engagement between said second follower means and said second cam means to thereby enable said biasing means to move said second gripper toward said first gripper.
 9. Apparatus as defined in claim 1, wherein said conveyor comprises an endless chain and a plurality of additional holders mounted on said chain, said holders being equidistant from each other.
 10. Apparatus as defined in claim 1, wherein said conveyor comprises an endless chain having a plurality of links and pintles articulately connecting said links to each other, said first gripper being pivotably connected with at least one of said pintles.
 11. Apparatus as defined in claim 10, wherein said first gripper has a front portion and a rear portion, as considered in the direction of movement of said holder along said path, said front portion being pivotably connected with said one pintle and said rear portion having at least one elongated groove receiving another one of said pintles. 